Swingworker with FileVisitor class and walkFileTree(), which iterates internally over a “set” of files in a directory tree; where to publish()?

Question

It seems like the long-running tree walker task should be defined in a class like so:

  public class TreeWalker extends SwingWorker implements         


        

Answer 1

It's not that I gave up on SwingWorker, I just determined that I didn't know squat about threads and decided to do something about it. My success the past 2 days with a much simpler project led me to apply that same strategy to my (various) Treewalker (projects), which now: (1) do not make the screen flash when appending output to a textarea and (2) end gracefully and immediately with a buttonpress.

All it took was using a separate thread (not a SwingWorker) for the "background" FileVisitor task, which: (a) let GUI stay "in charge" and thus be able to accept output seamlessly as well as provide a button for the user to press to abort and (b) makes the code look sane and easy to follow.

So @Mad, thanks AGAIN for the help. (I haven't been working solely on this since Nov. 19! I got so frustrated I just left it, did other stuff successfully, and got the nerve to come back and try again).

P.S. I found the text Ivar Horton's Beginning Java (7) invaluable. Best I've seen about threads.

FWIW here's an outline of my backup program:

public class Copy extends Thread{

  public static FileVisitResult disposition = FileVisitResult.CONTINUE;
  static Thread           t ;
  static FilesCopied      output ;   
...
  public static TreeWalker      fv;
...

  public void run() {    
...
    fv             = new TreeWalker();  
    try {
      Files.walkFileTree(UserIO.inputPath,fv);
    }
    catch ...
  }

  public /* inner */ class TreeWalker implements FileVisitor {
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
      maybeCopy(file);
      return disposition;
    }
    public FileVisitResult preVisitDirectory(Path d, BasicFileAttributes a) throws IOException {
      maybeMakeDir(d,fromRootDepth);
      return disposition;     
    }
... 
  } // end TreeWalker

...
  public static void main(String[] args) throws IOException {
    EventQueue.invokeLater(new Runnable()  
      public void run() { gui = new UserIO(); gui.setVisible(true); 
    }});  
    EventQueue.invokeLater(new Runnable() {
      public void run() {
        output = new FilesCopied();
      }});
    t = new Copy();
  }
} // end class Copy
======================
public class UserIO extends JFrame {
...
  public void btnBackupMouseClicked(MouseEvent evt) throws IOException { 
...
      Copy.t.start();
  }

  public void btnStopMouseClicked(MouseEvent evt) throws IOException { 
    Copy.disposition = FileVisitResult.TERMINATE;
  }                                      
}